FIELD OF THE DISCLOSURE
[0001] The present application relates to aircraft structures. In particular, the present
application relates to an aircraft wing-to-fuselage joint with an active suspension
connection.
BACKGROUND
[0002] Fixed-wing aircraft generally include a fuselage and a main wing that supports the
fuselage. Aerodynamic forces upon the main wing are transmitted from the wing to the
aircraft fuselage, and the load of the fuselage is imposed upon the main wing. The
wing-to-fuselage joint, or the structural connection between the main wing and the
fuselage, is thus a major component of the airframe. Through this connection the wing
transmits significant structural loads to the aircraft fuselage, including forces
that move the aircraft as a whole and also structural stresses such as bending stress,
torsional stress, vibration, etc.
[0003] Different variants of fixed wing-to-body joints, each having various limitations,
have been used on commercial aircraft for decades. Currently, there are several common
structural configurations for joining the main wing to the fuselage of a commercial
airplane. These various configurations generally present a structurally indeterminate
wing-to-body connection which requires the fuselage structure to be capable of sustaining
deflections imposed by wing bending. These deflections present the significant issue
of fuselage deformation as a result of wing bending.
[0004] Stress transmitted from aircraft wings into the fuselage via the wing-to-body joint
is a significant concern in aircraft design, since it affects the strength, durability
and other aspects of the aircraft. Existing rigid wing attachment points present limitations
to the fuselage/wing construction and sizing due to deflections imposed upon the fuselage
by wing bending. For example, many known wing-to-body joints transfer wing bending
moments directly to the fuselage. Other known wing-to-body joints can at least partially
isolate the fuselage from wing bending moments, but the fuselage contour can still
be forced out of shape by horizontal and vertical forces upon the wing. Also, some
prior wing-to-body joint solutions generally do not separate wing torsion and vibration
modes from the fuselage pitch mode as a contributor to wing flutter phenomena. In
addition to structural and operational effects on the airframe, many existing wing-to-body
joint configurations have significant limitations in suppressing turbulence effects
and wing-mounted engine vibrations, which have great effects on passenger comfort.
[0005] The present application is directed toward at least one of the above-mentioned concerns.
SUMMARY
[0006] In accordance with one embodiment thereof, the present disclosure provides an aircraft
including a fuselage, a wing, and a decoupled joint, interconnecting the fuselage
and the wing.
[0007] In accordance with another embodiment thereof, the disclosure provides an aircraft
having a fuselage, a main wing, and an active suspension system, interconnecting the
fuselage and the main wing.
[0008] In accordance with another embodiment thereof, the disclosure provides a method of
adapting an aircraft to attenuate forces between a wing and a fuselage thereof. The
method includes providing a plurality of sensors upon the aircraft, configured for
sensing motion and/or mechanical stress of the wing and/or the fuselage and producing
signals indicative thereof, and providing a plurality of active suspension elements
interconnecting the wing and the fuselage, the active suspension elements being configured
to move at least in response to the signals, to adjust a position of the wing.
[0009] Further, the disclosure comprises embodiments according to the following clauses:
Clause 1: An aircraft, comprising: a fuselage; a main wing; and an active suspension
system, interconnecting the fuselage and the main wing.
Clause 2: The aircraft of clause 1, wherein the active suspension system further comprises:
a plurality of actuators, connected between the wing and the fuselage, configured
to selectively adjust a relative position of the wing and fuselage in response to
dynamic loads upon the wing and/or the fuselage; a plurality of sensors, attached
to at least one of the wing and the fuselage, each sensor configured to produce a
sensor signal indicating a motion and/or stress condition at a location of the respective
sensor; and a controller, configured to receive and analyze signals from the plurality
of sensors, and to control the plurality of actuators in response to the sensor signals,
to dynamically adjust the position of the wing in response to forces from and/or motion
of the wing.
Clause 3: The aircraft of clause 2, wherein the controller comprises a microcomputer
device, including a processor and system memory, provided with programming code including
an actively suspended wing model, further configured to receive and analyze input
from a flight control system, flight parameters, and pilot or autopilot input, and
to provide output based on the actively suspended wing model, to dynamically control
the actuators.
Clause 4: The aircraft of clause 2, wherein the active suspension system comprises
at least four actuators connected between the wing and the fuselage.
Clause 5: The aircraft of clause 1, further comprising a flexible wing-to-body fairing,
enclosing the active suspension system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010]
FIG. 1 is a perspective view of an embodiment of an aircraft having a wing-to-body
joint with an active suspension system in accordance with the present disclosure;
FIG. 2 is a cross-sectional view of an aircraft fuselage at the wing joint location,
the aircraft having a pickle fork-type wing-to-body joint.
FIG. 3 is a cross-sectional view of an aircraft fuselage at the wing joint location,
the aircraft having a pin-type wing-to-body joint.
FIG. 4 is a cross-sectional diagram of an aircraft fuselage at the wing joint location,
the aircraft having an embodiment of a wing-to-body joint with an active suspension
system in accordance with the present disclosure.
FIG. 5 is a side view of the aircraft fuselage and wing structure of the embodiment
of FIG. 4, showing the fore-to-aft location of actuator components of the wing-to-body
joint active suspension system.
FIG. 6 is schematic diagram of an embodiment of a wing-to-body joint active suspension
system in accordance with the present disclosure.
FIG. 7 is a block diagram of a signal processing control system for a wing-to-body
joint active suspension system in accordance with the present disclosure.
FIG. 8 is a block diagram of an embodiment of control system relationships for a wing-to-body
joint active suspension system in accordance with the present disclosure.
FIG. 9 is a block diagram of an embodiment of the elements of an active wing suspension
control system in accordance with the present disclosure.
FIG. 10 is a top perspective view of an aircraft having an embodiment of a wing-to-body
joint active suspension system in accordance with the present disclosure.
FIG. 11 is a bottom rear perspective view of the aircraft of FIG. 12.
FIG. 12 is a close-up perspective view of one set of rear spar active suspension struts.
FIG. 13 is a bottom front perspective view of the aircraft of FIG. 12.
FIG. 14 is a close-up perspective view of the forward spar active suspension struts.
FIG. 15 is a conceptual side view of two aircraft, showing the landing and takeoff
configuration of a conventional fixed wing, compared to the flared wing of an aircraft
having an active suspension system interconnecting the wing and fuselage.
FIG. 16 is a partial cross-sectional view of an aircraft fuselage and active wing
joint location, showing one embodiment of a flexible wing-to-body fairing.
[0011] While the disclosure is susceptible to various modifications and alternative forms,
specific embodiments have been shown by way of example in the drawings and will be
described in detail herein. However, it should be understood that the disclosure is
not intended to be limited to the particular forms disclosed. Rather, the intention
is to cover all modifications, equivalents and alternatives falling within the spirit
and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION
[0012] Shown in FIG. 1 is an aircraft 100, generally including a main wing 102, an elongate
fuselage 104 supported approximately at its midpoint upon the main wing 102, and having
a rudder 106 and elevators 108 at the tail 110 of the aircraft. As used herein, the
term "main wing" has reference to the entire main wing structure of the aircraft 100,
including both the left and right portions of the main wing. Thus, the aircraft shown
in FIG. 1 includes a single main wing 102, having left and right portions. The aircraft
100 also includes engines 112 for providing propulsion, which in this case are turbojet
engines mounted upon pylons 114 below the main wing 102. The aircraft 100 also includes
an aerodynamic fairing 116 that provides a smooth external transition between the
main wing 102 and the fuselage 104 of the aircraft. This wing-to-body fairing 116
encloses the region in which the fuselage 104 is joined to the main wing 102, and
can also enclose the aircraft landing gear and other components (not shown).
[0013] It is to be understood that the aircraft 100 shown in FIG. 1 is only one of many
types of configurations of fixed-wing aircraft, and application of the present disclosure
is not limited to this particular configuration. Nor is the system disclosed herein
limited to commercial aircraft or aircraft of any particular size. Aircraft of different
sizes, having different types of engines, different wing configurations, etc. can
be configured with a wing-to-body joint having an active suspension system, in accordance
with the present disclosure.
[0014] As noted above, aerodynamic forces upon the main wing of a fixed-wing aircraft are
transmitted from the wing to the aircraft fuselage through the wing-to-fuselage joint.
Through this joint the wing transmits significant structural loads including bending
stress, torsional stress, vibration, etc. into the rest of the airframe. Typical rigid
wing attachment points present limitations to the fuselage/wing joint due to the force
deflections imposed upon the fuselage by bending of the wing. Stress transmitted from
aircraft wings into the fuselage via the wing-to-body joint is a significant concern
in aircraft design, since it affects the strength, durability and other aspects of
the aircraft.
[0015] Currently, there are several common structural configurations for joining the main
wing to the fuselage of a commercial airplane. Two common variants of fixed wing-to-body
joints are shown in FIGs. 2 and 3. Shown in FIG. 2 is a cross-sectional view of an
aircraft 200 having a main wing 202 and a fuselage 204. This aircraft 200 includes
what is called a "pickle fork" fitting at the front and rear main spars of the main
wing. In the cross-sectional view, a main spar 212 of the wing is visible, to which
a pair of pickle fork fittings 210 are fixedly attached. The pickle fork fittings
210 extend upward into the side wall of the fuselage 204, and thus transmit horizontal
and vertical forces, represented by arrows 214, and bending moments, represented by
arrows 216, from the wing 202 into the fuselage 204. Because of this configuration,
when the wing 202 deflects, as shown in dashed lines at 220, the pickle fork fittings
210 also deflect, as shown in dashed lines at 218, causing corresponding deflection
and deformation of the fuselage 204. It is to be understood that the magnitude of
deflection of the wing 202 shown at 220 and of the pickle fork members 210 shown at
218 in FIG. 2 may be exaggerated for illustrative purposes.
[0016] Some aircraft employ a combination of a "pickle fork" fitting at the front spar,
a trap panel at the rear spar, and a "flex-tee/Pi-fitting" over-wing attachment. The
term "trap panel" is well known to those of skill in the field of aircraft structures,
and is short for trapezoidal panel. A trapezoidal panel is a panel that is attached
to the rear spar of the main wing, in line with the fuselage skin. Its purpose is
to transfer loads between the fuselage and the wing. Trap panels are one step closer
to a wider spread load exchange between the wing and the fuselage. A flex-tee/Pi-fitting
combination is a structural feature that is commonly used to join aircraft fuselage
frames to the wing in the area above the wing top skin (i.e. the region of smaller
fuselage frames located above the wing between the front and rear spars of the wing).
This type of structure is well known to those of skill in the area of aircraft structures.
The flex-tee/Pi-fitting combination enables a flexible fuselage reaction to wing bending,
while retaining a relatively high capacity to withstand cabin pressure loads. While
pickle fork and other types of connections provide a relatively rigid wing-to-body
joint, vertical and horizontal forces as well as bending moments are transferred from
the wing to the fuselage, causing the fuselage shape to change depending on the amount
of wing displacement under aerodynamic loads. These wing attachment configurations
can therefore produce fuselage deformation as a result of wing bending.
[0017] Another type of wing-to-body joint that is used in commercial aircraft is the pin-type
joint, and example of which is shown in FIG. 3. This cross-sectional view shows an
aircraft 300 having a main wing 302 and a fuselage 304. In this configuration, the
fuselage 304 is connected to the structure of the main wing 302 with pin joints 310
that connect between the fuselage 304 and the main spar 312 of the wing. These pin
joints 310 at least partially isolate the fuselage 304 from wing bending moments.
Pin type wing-to-body joints transmit horizontal and vertical forces, indicated by
arrows 314, into the fuselage, but prevent wing bending moments from being transferred
directly to the fuselage. However, the fuselage contour can still be forced out of
shape by the reaction of the horizontal and vertical forces through the pin joints,
as indicated by the deformed fuselage contour shown in dashed lines at 316. It is
to be understood that the magnitude of deflection of the wing fuselage 304 shown at
316 in FIG. 3 may be exaggerated for illustrative purposes.
[0018] There are other known wing-to-body joint configurations in addition to those shown
in FIGs. 2 and 3, but they all tend to transmit stress from the wing structure into
the fuselage, and thus cause deformation of the fuselage. In addition, many wing-to-body
joint configurations do not significantly separate wing torsion and vibration modes
from the fuselage pitch mode as a contributor to wing flutter phenomena. Many existing
wing-to-body joint configurations also have significant limitations in suppressing
turbulence effects and wing-mounted engine vibrations, which have great effects on
passenger comfort.
[0019] Advantageously, as disclosed herein, a decoupled wing-to-body joint has been developed
that can reduce the deflections and stress imposed upon an aircraft fuselage by wing
bending, and can also reduce the effects of turbulence upon passenger comfort. As
used herein, the term "decoupled" is intended to mean a joint in which the wing is
not fixedly or rigidly or even merely pivotally connected to the fuselage. The decoupled
joint disclosed herein decouples the entire main wing, rather than merely a portion
of it, as is the case in swing-wing aircraft, for example. In a "decoupled" joint,
as that term is used herein, the wing can move with respect to the fuselage in up
to six degrees of freedom (i.e. motion in x, y, and z directions, and rotation about
the x, y and z axes). In one embodiment, the decoupled wing-to-body joint disclosed
herein includes a power-actuated, computer-controlled active suspension system that
connects the aircraft main wing to the fuselage. The active suspension is integrated
into the airplane in order to reduce the transmission of wing bending-induced static
loads to the fuselage structure, to dampen the dynamic loading that is transferred
from the wing to the fuselage, and to actively control dynamic interaction between
the fuselage and the main wing in such cases as turbulence and flutter.
[0020] Fundamental principles of active suspension systems have been integrated into automotive
and some other products. Traditional suspension systems that have been used in automobiles
and other applications have traditionally relied upon a combination of springs and
shock absorbers to dampen impact loads and help maintain a relatively constant orientation
of the vehicle. More recently, active suspension systems have been developed that
rapidly sense changes in loads and vehicle motion, and actively operate to counter
them.
[0021] Active suspension systems for motor vehicles have been developed by Bose Corporation
and Lotus Engineering, USA, for example. Such systems typically use an actuator, such
as a linear electromagnetic motor, at each wheel of the vehicle in lieu of a conventional
shock-and-spring setup. Unlike conventional fluid-based shock absorbers (dampers),
the actuators in an active suspension system are not limited by their own inertia.
Instead, the actuators can extend and compress at a much greater speed than conventional
shock absorbers, and do so under the command of a computer controller, which extends
or retracts the actuator in real time in response to sensor inputs and other data.
These sensors detect motion of different parts of the vehicle, and the controller
can receive the sensor input and make adjustments to the system fast enough that adjustments
are made before the vehicle inertia is overcome by any new force or stress. Increasingly
fast computing capabilities and the increasing reliability of mechanical actuating
systems are part of what has made active suspension systems a reality. The speed of
the computer controller can compensate for a much wider range of motion, shock and
vibration in the vehicle than is possible with conventional shock and spring configurations.
For example, the motion of each wheel of an automobile can be controlled so that the
body of the car remains substantially level regardless of what's happening at each
wheel. The actuators of an active suspension system can also counteract the body motion
of the car while accelerating, braking and cornering, giving the driver a greater
sense of control and reducing pitching and rolling of the vehicle cabin.
[0022] While active suspension systems are known in the automotive world, it does not appear
that the concept of an active suspension system has previously been applied to the
wing-to-body joint of an aircraft. One embodiment of a wing-to-body joint having an
active suspension in accordance with the present disclosure is shown in FIGs. 4-5.
Provided in FIG. 4 is a cross-sectional diagram of a fuselage 402 and wing 404 of
an aircraft 400, the cross-section taken at the wing joint location. Provided in FIG.
5 is a side view of the fuselage 402 and sectional view of the wing structure 404
of the aircraft 400, showing the fore-to-aft location of actuator components of the
wing-to-body joint active suspension system. The views of FIGs. 4 and 5 are taken
at right angles to each other, and the relative x, y and z coordinate axes are shown
in the respective views.
[0023] A wing-to-body joint having an active suspension system, as disclosed herein, provides
computer-controlled hydraulic or electro-magnetic actuators 414 at the main attachment
points in the wing-to-fuselage joint. The actuators 414 are strategically grouped
and connected to at least the four major wing-to-fuselage joints or connection points.
Two forward actuator/connection units 406 can be provided at the front spar 408 and
two rear actuator/connection units 410 are provided at the rear spar 412. The actuator/connection
units 406, 410 are designed to effectively control all six degrees of freedom (i.e.
motion in x, y, and z directions, and rotation about the x, y and z axes) of the wing
404 relative to the fuselage 402. Each actuator unit 406, 410 includes a pair of motion
transducers 414, such as hydraulic cylinders, coupled to the pivot points of a scissor
mechanism 416. Extension or retraction of the motion transducers 414 causes the respective
scissor mechanism 416 to extend or retract, thus changing the distance between the
wing 404 and fuselage 402 at the location of the particular actuator. This allows
the wing 404 to be tilted at-will with respect to two orthogonal axes in a horizontal
plane.
[0024] Since side-to-side and fore-to-aft motion of the wing 404 relative to the fuselage
402 is not desired, the connections at the front spar 408 and rear spar 412 with the
scissors mechanisms 416 allows up and down motion at each connection point, but resists
side-to-side motion. In the configuration shown in FIGs. 4 and 5 the forward scissor
mechanisms 416 are oriented generally perpendicular to the aft scissor mechanisms
416. The scissor mechanisms 416 of the forward actuator units 406 are connected to
the base structure 426 of the fuselage 402 at forward pin connections 418. The scissor
mechanisms 416 of the rear actuator units 410 are connected to the base structure
426 of the fuselage 402 at aft pin connections 422 of a mounting bracket 424. With
this configuration, attenuated vertical forces, represented by arrows 420, are transmitted
into the fuselage 402, but the fuselage is substantially isolated from lateral forces
and bending moments being transmitted from the wing, and side-to-side and fore-to-aft
motion of the wing 404 relative to the fuselage 402 is resisted.
[0025] FIG. 6 provides a schematic diagram of an embodiment of a wing-to-body joint active
suspension system 600 in accordance with the present disclosure. The system 600 generally
includes a central computer controller 601, sensors 602, actuators 604, a power source
606, and flight control system 607. While only one actuator 604 is shown, this is
intended to be representative of multiple actuators, also referred to herein as active
suspension elements. In the schematic diagram of FIG. 6, "Disturbance" 608 represents
any surrounding affect exerted on the airplane, such as the effect of air turbulence,
symbolically represented as a semi-soft contact of the turbulent air to the wing surface.
The wing structure, indicated generally at 609, is represented to include a mass 610,
denoted m
wing, a level of structural elasticity suggested by a spring 612 and denoted k
w, and a shock absorbing capacity suggested by a damping strut 614 and denoted c
w. For purposes of this diagram, the fuselage 615 is represented as a mass 616 labeled
m
fus.
[0026] The active suspension system 603 is interposed between the fuselage 615 and the wing
609, and includes three physical characteristics: a level of structural elasticity
suggested by a spring 618 and denoted k, a shock absorbing capacity suggested by a
damping strut 620 and denoted c, and a variable dynamic force suggested by an actuator
604 and denoted f. In practice, the variable dynamic force and some or all of the
structural elasticity and damping is provided by the multiple actuators 604 of the
active suspension system 603. Control inputs to these physical actuators can be provided
by hydraulic or electro-mechanical servos (not shown). Each actuator 604 can be an
active suspension strut, which can be a hydraulic, pneumatic, electromechanical, or
any other type of suitable force and motion device. The actuator 604 is under direct
control of the controller 601, and actively extends or retracts in real time in response
to commands (i.e. output signals) from the controller 601 to change the position of
the wing 609. This real-time control of the wing position and orientation and of the
wing-fuselage connection allows dynamic control of the actuators 604 in direct response
to flight conditions.
[0027] The sensors 602 measure the relative position and/or motion of different parts of
the aircraft and different components of the active suspension system 603 and provide
sensor signals to the controller 601. One exemplary arrangement of sensors is schematically
illustrated in FIG. 1. The aircraft can include multiple sensors 602 along the main
wing 102, sensors 602 in the fuselage 104, and sensors 602 associated with the actuators
604 and/or joints of the active suspension system 603, which are shown in FIG. 6.
A variety of sensor types can be used, including accelerometers, mechanical stress
sensors, proximity sensors, position sensors, orientation sensors, etc. The sensing
systems can be configured and positioned to detect vibration, tension, flexion, speed,
position, direction, acceleration and other factors, in addition to the sensors that
are normally included in aircraft that do not have an actively-suspended wing control
system.
[0028] The signals from the sensors 602 become part of the input signals to the computer
controller 601 that controls the active suspension system 603. The controller 601
can be a microcomputer device that is provided with a processor and system memory,
and programming code for controlling the actuators in response to sensor and other
input to modulate dynamic system response. The controller 601 and related components
provide control system electronic processing hardware, including a real-time, high
bandwidth processor that can receive numerous feedback signal inputs. This processor
601 can include multiple processors or a multicore CPU that is programmed to execute
distributed threads of control system application software or firmware. Alternatively,
the processor can be a field-programmable gate array (FPGA) with a digital signal
processor (DSP) configured to handle the time requirements and complexity of active
wing suspension control laws.
[0029] The control system software, which is stored in memory in the controller 601, is
based on an understanding of aircraft dynamic system behavior, and provides corresponding
software code for effectively controlling the wing-to-body connection. The software
can include an aircraft system model, and an actively-suspended wing model, and is
configured to provide output via those models based on input signals from the system
sensors 602, feedback from the flight control system 607, flight parameters, and conditioned
inputs from the flight control system 607 as a result of pilot or autopilot input.
Very fast computing speeds and increasing reliability of mechanical actuating systems
allow the application of adjustable dynamic systems in primary structural joints on
an aircraft, and allows the controller 601 to dynamically control the actuators 604.
The central computer 601 receives dynamic input signals from the sensors 602 at various
locations on the aircraft, and combines and/or compares the sensor readings with other
data, such as airspeed, attitude and other indicators, such as from the flight control
system (FCS) 607. Using custom-created software, the computer controller 601 can calculate
an optimal dynamic response and send output in the form of command signals to the
actuators 604. The actuators 604 dynamically adjust relative position between the
main wing 609 and the fuselage 615 in response to the output signals from the controller
601 to compensate for relative motion of the wing and fuselage, as detected by the
sensors 602.
[0030] The active wing suspension control system 600 also includes a signal distribution
system 622, which provides a network of connections (e.g. electrical wires, hydraulic
conduits, etc.) to support control of the actuators 604 and to direct sensor feedback/input
signals from sensors 602 and other sources to the controller 601. As will be appreciated
by those of skill in the art, the signal distribution system 622 can also include
redundant signal distribution and actuator feedback networks (not shown) as a safety
feature. Power supplies 606 and/or power supply paths to the subsystem components
can also be made redundant to aid system reliability.
[0031] From a dynamic perspective, the system 600 operates by monitoring and recording wing
motion parameters, monitoring and recording fuselage motion parameters, comparing
wing and fuselage motion signals in the controller unit 601 and applying corrective
actuation via the active suspension system 603 between the wing and fuselage. The
corrective actuation is calculated to reduce and/or eliminate fuselage short wave
dynamic motion induced by wing vibrations (turbulence or flutter). From a static loading
perspective, the system helps to reduce or eliminate fuselage deformations induced
by wing bending, and can also be used to adjust the relative position of the wing
and fuselage at specific phases of flight, such as takeoff and landing. This latter
feature can help reduce the need for high lift devices, and is discussed in more detail
below.
[0032] Shown in FIGs. 7-9 are block diagrams that show the major components and functional
interactions of an embodiment of the active wing suspension control system. Shown
in FIG. 7 is a block diagram of a signal processing control system 700 showing how
the wing-to-body joint active suspension system is integrated with the aircraft flight
control system 702. The flight control system 702 provides input, such as airspeed,
altitude, attitude, as well as flight control surface status, etc., to an FPGA embedded
system 601, which is the controller that controls the active suspension system (603
in FIG. 6). The FPGA 601 is programmed to run a state machine corresponding to the
selected system control law. It is supported by high-throughput random access memory,
and includes drivers 706 for the actuators/servos. These drivers provide the actual
actuator control signals, which are sent to the actuators 604.
[0033] The actuators or servos 604 include sensors or transducers 602 to detect actual motion
of these devices. These sensors 602 provide feedback to the drivers for the transducer
signals 712, which convert these signals into input back to the FPGA 601. In this
way, a feedback loop is created in which the signals that are sent to the actuators
604 can be continually adjusted based on actual operation of the actuators, as well
as commands of the system to adjust for external effects on the aircraft.
[0034] The block diagram of FIG. 8 illustrates one embodiment of the control system relationships
800 for a wing-to-body joint active suspension system in accordance with the present
disclosure. As a pilot or an autopilot system operates the aircraft, the flight control
system 607 (e.g. flight control computer) receives conditioned inputs 802 from the
pilot or autopilot. These inputs include commands for aircraft control surfaces, engines
and other mechanical systems affecting flight performance that are not specifically
related to the active wing suspension control system. The flight control system 607
also receives input from flight control sensors 806. This can include sensor input
from flight control system components that are not specific to the active wing suspension
system, such as servo feedback from flaps, rudder, or elevator actuators, for example,
as well as input from altitude, airspeed, attitude, and other indicators that are
associated with the flight control system 607.
[0035] The flight control system 607 interfaces with the active wing suspension system controller
601, described above with respect to FIG. 6. The active wing suspension control system
601 can be programmed into the same physical computing device that also includes the
flight control system 607, or it can be associated with a separate computing device.
The active wing suspension control system further receives input from the active wing
suspension sensors 602, which include the sensors on the wings, fuselage and sensors
associated with the active suspension joint actuators 604 and related devices, as
discussed above. The sensors associated with the active suspension joint actuators
604 and related devices in turn receive and report inputs that come from the active
suspension components, allowing the feedback loop discussed in FIG. 7 to operate.
[0036] Provided in FIG. 9 is a block diagram showing the elements of an active wing suspension
control system 900 in accordance with the present disclosure. Flight control input
902, as discussed above and indicated at least in part by block 802 in FIG. 8, is
provided to the active wing suspension control system 601, which includes a processor
that is programmed with the control laws for the active wing suspension, as discussed
above. The active wing suspension control system also receives input from sensor feedback
906, as discussed above. With these inputs, the processor 601 provides signals to
an output generator 908, which provides real-time control signals to the actuators
604, numbered 1 to N, of the active suspension system. The control system generates
appropriate outputs for the actuators 604 based on control laws derived from the airplane
active suspension model and flight performance parameters from other aircraft resources
such as the control surfaces and vehicle models. As discussed above, the actuators
604 produce positional and/or performance feedback signals via active wing suspension
system sensors 602, and this sensor data, along with signals from additional sensors
602, such as wing and fuselage sensors 602, shown in FIG. 1, can also be provided
to precisely control the active suspension system for desired aircraft performance.
The sensor feedback 906 is provided to the processor 601, and is also provided as
flight control feedback 914 to the flight control system, so that the aircraft operator
can be aware of the operational status of the active suspension system. The active
suspension system can also be configured to allow operator control inputs in certain
circumstances, such as for wing flare during takeoff or landing.
[0037] The system described above thus provides an active suspension that moves the wing
relative to the body of an aircraft to avoid disturbances, rather than the disturbance
moving the wing. This system can provide many benefits. It can improve passenger comfort
by significantly reducing turbulence effects and passenger cabin vibrations caused
by the transmission of wing bending and vibration and wing-mounted engines. This softens
the ride for passengers.
[0038] Another embodiment of a wing-to-body joint with an active suspension system is shown
in FIGs. 10-14. Shown in FIG. 10 is a top perspective view of an aircraft 1000 having
an embodiment of a wing-to-body joint active suspension system 1002 in accordance
with the present disclosure, and FIG. 11 is a bottom rear perspective view of the
same. In these views the wing-to-body fairing (116 in FIG. 1) is removed to reveal
the components of the wing-to-body joint 1002, and the main landing gear and related
structures, which normally lie just aft of the main wing 1004, are not shown. Additionally,
the wings 1004 are truncated and simplified, to show only the front spar 1006 and
rear spar 1008, with general connecting structure therebetween. For illustrative purposes,
the full wing span is not shown, and the leading and trailing edges of the wings,
along with related wing structures are not shown. As with aircraft generally, the
fuselage 1010 includes passenger windows 1012 and an emergency egress door 1014 over
the main wing 1004. The lower part 1016 of the fuselage can include a forward cargo
hold forward of the main wing 1004, and an aft cargo hold aft of the main wing 1004
and the landing gear bay region.
[0039] In the embodiment of FIGs. 10-14, the front main spar 1006 and rear main spar 1008
of the wing 1004 are attached to the floor 1020 of the aircraft fuselage 1010 via
four groups 1018 of actuators, two attached at the left and right sides of the forward
main spar 1006, and two attached at the left and right sides of the aft main spar
1008. These actuators can be hydraulic cylinders or other actuators. In this embodiment,
each group 1018 of actuators includes three hydraulic cylinders 1022, attached to
their respective spar in substantially orthogonal relationship. The actuators 1022
shown in FIGs. 10-14 are exemplary only, and are not necessarily intended to represent
the actual size and shape of actuators that are or can be used in this application.
However, those of skill in the art will recognize that since the primary forces that
lift and control the aircraft act upon the main wing 1004, the connection between
the wing 1004 and the fuselage 1010 must be sufficiently strong to withstand these
forces in a wide variety of situations.
[0040] Shown in FIG. 12 is a close-up perspective view of one set or group 1018 of active
suspension struts 1022 at the rear spar 1008. These struts 1022 are pivotally attached
to a structural lobe 1024 protruding from the rear of the rear spar 1008, and pivotally
attached to floor 1020 of the aircraft fuselage 1010. The struts 1022 are oriented
substantially perpendicular to each other, generally defining a downwardly-pointed
corner of a tetrahedron oriented at about a 45° angle relative to the axes of the
aircraft 1000. This configuration allows each of the struts 1022 to affect the position
and motion of the wing 1004 with respect to all of the three standard axes (x, y and
z axes) of the aircraft. By virtue of the angle of the struts in relation to the aircraft,
in the configuration shown in FIG. 12, two of the struts 1022a, b, are aligned to
have a fore-to-aft component of motion (in addition to a vertical component of motion),
while the third strut 1022c does not, and only provides a side-to-side component of
motion. The opposing lateral side of the rear main spar 1008 includes a similar group
1018 of three struts.
[0041] On the other hand, as shown in FIGs. 13 and 14, the actuators 1022 attached to the
front main spar 1006 are also arranged in an inverted tetrahedral arrangement, with
two of the struts 1022d, e, aligned to have a side-to-side component of motion (in
addition to a vertical component of motion), while the third strut 1022f in this group
only provides a fore-to-aft component of motion. The opposing lateral side of the
front main spar 1006 includes a similar group 1018 of three struts. This arrangement
of the active suspension struts 1022 thus provides twelve total struts 1022 connecting
the wing 1004 to the fuselage 1010 of the aircraft 1000, with six of the struts 1022
having a side-to-side component of motion, six of the struts having a fore-to-aft
component of motion, and four struts 1022, one at each corner of the wing 1004 in
the suspension region, having only a side-to-side or fore-to-aft component of motion,
in addition to any vertical component of motion. This provides the active suspension
1002 with substantially equal and symmetrical strength in all directions of possible
motion of the wing 1004.
[0042] Though not shown in FIGs. 10-14, additional attachment devices can be provided between
the wing 1004 and the aircraft fuselage 1010. For example, in addition to the active
suspension elements, passive connection devices, such as struts, passive linkages
and scissor devices like those shown in FIGs. 4 and 5, but without active suspension
elements, can also be provided to increase the strength of connection of the wing.
Additionally, safety devices and/or redundant connections can be provided in case
of failure of any of the active wing suspension system components.
[0043] As noted above, the active suspension system disclosed herein can also be used to
change the angle of attack of the main wing without moving the fuselage. This can
allow independent control of the wing pitch angle relative to the fuselage, thus reducing
the flare angle of the aircraft fuselage during takeoff and landing. Shown in FIG.
15 are conceptual side views of two aircraft in a landing or takeoff configuration.
The first aircraft 1502 shown at the top of FIG. 15 is a conventional fixed wing aircraft,
with a main wing 1504 in a fixed orientation relative to the aircraft fuselage 1506.
During takeoff and landing, flaps 1508 are extended from the trailing edge of the
main wing 1504 to provide additional lift and control of the aircraft. However, during
actual takeoff or landing, the pitch of the whole aircraft 1502 is flared, with the
nose 1507 up and the tail 1509 down. During takeoff this is done to change the angle
of attack of the wing 1504 to allow the aircraft to climb. During landing, this is
done to slow the aircraft and to take full advantage of ground effects. In both cases,
if the flare of the aircraft 1502 is too great, there is a danger of a tail strike.
[0044] Advantageously, in addition to the advantages in the ability to modulate dynamic
interaction between the wing and the fuselage that the present system provides, the
active suspension system disclosed herein can also be used to adjust the relative
wing/fuselage position for takeoff and landing. That is, the pitch of the main wing
relative to the fuselage can be adjusted to lift the aircraft prior to fuselage roll
during takeoff, and to provide the proper wing flare for landing while having a reduced
flare of the whole aircraft, thus reducing the risk of a tailstrike on landing. Shown
in the bottom portion of FIG. 15 is an aircraft 1510 having a main wing 1512 and a
fuselage 1514. In this aircraft, the main wing 1512 is attached to the fuselage 1514
via an active suspension system 1518, as described above. The active suspension system
1518 allows the entire main wing 1512 to be flared relative to the fuselage 1514.
This allows the angle of attack of the wing 1512 to be adjusted without any change
in the pitch of the aircraft fuselage 1514, which helps reduce the need for high lift
devices such as flaps. Specifically, in the image shown at the bottom of FIG. 15,
the wing 1512 includes a single flap 1516, rather than the more extensive double flap
1508 on the conventional fixed wing 1504. The ability to adjust the pitch angle between
the fuselage 1514 and the main wing 1512 can help minimize the risk of tailstrike
during takeoff or landing, and can thus potentially eliminate the need for tailstrike
pads. This can be particularly beneficial in the development of stretch models of
existing aircraft, for example, which otherwise can involve modifying landing gear
and other significant modifications.
[0045] With a main wing having an adjustable angle or position relative to the fuselage,
a flexible wing-to-body fairing can be provided to provide a smooth transition surface
between the wing and the fuselage, while also maintaining desired aerodynamic operation.
Shown in FIG. 16 is a partial cross-sectional view of an aircraft fuselage 1610 and
wing 1612 in the vicinity of an active wing-to-body joint 1608, showing one embodiment
of a flexible wing-to-body fairing 1614. This fairing 1614 includes a fixed fairing
support 1616, which is attached to the side of the aircraft fuselage 1610 above the
wing 1612. A rub strip 1618 is provided on the top surface of the wing 1612, and a
flexible and moveable fairing extension 1620 extends between the fixed fairing support
1616 and the rub strip 1618. As the wing 1612 moves relative to the fuselage 1610
of the aircraft, the fairing extension 1620 slidably extends and retracts between
the wing 1612 and the fuselage 1610, thus enclosing the wing-to-body joint 1608, while
allowing relative motion of the respective parts. Similar flexible wing-to-body fairing
joints can also be provided at the leading and trailing edges of the wing 1612, and
at fore and aft lower body transition regions. It is to be understood that this configuration
of a flexible wing-to-body fairing is only one possible configuration, and other configurations
can also be used.
[0046] The application of the decoupled wing-to-fuselage joint disclosed herein thus helps
to alleviate loads going into the fuselage structure, helps eliminate fuselage deformation
induced by wing bending, and helps resolve some design and static/fatigue sizing constraints
imposed by more conventional rigid and fixed-point wing-to-fuselage attachments. With
a decoupled wing-to-fuselage joint, structural loads that transfer from the wing to
the fuselage are reduced to the dampened vertical force components, which can provide
a more weight-efficient design of the fuselage and wing joint support structure.
[0047] By decupling the fuselage and the wing, this active suspension system can also reduce
wing flutter effects, so that wing oscillations are dampened. The computer-controlled
wing-to-fuselage joint/interaction can allow isolation and control of fuselage modes
of vibration independent of corresponding wing vibration modes, thereby alleviating
one of the common sources of wing flutter. That is, the system enables isolation of
the pitch modes of the fuselage from the torsion modes of the wing, and thereby helps
to alleviate wing flutter and vibratory modes. This can allow aircraft weight to be
reduced because flutter loads are reduced. This system also helps to reduce gust load
effects on the fuselage, and can also help enable the application of software that
manipulates load distribution between the wing and fuselage.
[0048] Although various embodiments have been shown and described, the present disclosure
is not so limited and will be understood to include all such modifications and variations
are would be apparent to one skilled in the art.
1. An aircraft, comprising:
a fuselage;
a wing; and
a decoupled joint, interconnecting the fuselage and the wing.
2. The aircraft of claim 1, wherein the joint is decoupled using a suspension system.
3. The aircraft of claim 2, wherein the suspension system is an active suspension system.
4. The aircraft of claim 3, wherein the active suspension system receives inputs and
adjusts a position of the wing to account for the inputs.
5. The aircraft of claims 3 -4, wherein the active suspension system further comprises
a plurality of actuators, connected between the wing and the fuselage, configured
to selectively adjust a relative position of the wing and fuselage in response to
dynamic loads upon the wing and/or the fuselage.
6. The aircraft of claim 5, wherein the active suspension system comprises at least four
actuators connected between the wing and the fuselage.
7. The aircraft of claim 6, wherein the active suspension system comprises four actuator
groups, each positioned at one of four corners of a wing main spar assembly, each
actuator group comprising three actuators oriented at substantially orthogonal angles.
8. The aircraft of claims 5 -7, wherein the active suspension system further comprises:
a plurality of sensors, attached to at least one of the wing and the fuselage, each
sensor configured to produce a sensor signal indicating a motion and/or stress condition
at a location of the respective sensor; and
a controller, configured to receive and analyze signals from the plurality of sensors,
and to control the plurality of actuators in response to the sensor signals, to dynamically
adjust the position of the wing in response to forces from and/or motion of the wing.
9. The aircraft of claim 8, wherein the sensors include at least one of stress sensors,
accelerometers, proximity sensors, position sensors and orientation sensors.
10. The aircraft of any preceding claim, wherein the decoupled joint can be manipulated
to flare the wing for takeoff and/or landing of the aircraft.
11. A method of adapting an aircraft to attenuate forces between a wing and a fuselage
thereof, comprising:
providing a plurality of sensors upon the aircraft, configured for sensing motion
and/or mechanical stress of the wing and/or the fuselage and producing signals indicative
thereof; and
providing a plurality of active suspension elements interconnecting the wing and the
fuselage, the active suspension elements being configured to move at least in response
to the signals to adjust a position of the wing with respect to the fuselage.
12. A method in accordance with claim 11, further comprising providing a controller, interconnected
between the plurality of sensors and the active suspension elements, the controller
configured to receive signals from the sensors and provide output signals to control
the active suspension elements to dynamically adjust the position of the wing in response
to forces from and/or motion of the wing.
13. A method in accordance with claim 12, further comprising interconnecting the controller
with a flight control system, flight parameters, and pilot or autopilot input, and
to provide output based on the actively suspended wing model, to dynamically control
the active suspension elements.
14. A method in accordance with claims 12-13, further comprising providing the controller
with programming code including an actively suspended wing model, configured to dynamically
compute adjustments to the position of the wing in response to forces from and/or
motion of the wing with respect to the fuselage.
15. A method in accordance with claims 12 -14, further comprising programming the controller
to actuate the suspension elements to adjust a pitch of the wing in connection with
takeoff or landing of the aircraft.